RFID enabled cabinet having temperature controlled drawer

ABSTRACT

An automated system and associated method for storing items comprises a cabinet having at least one refrigerated drawer using a temperature control device and a non-temperature controlled drawer. The drawer design is such that temperature gradients throughout the drawer are minimized. Faraday cages are provided about each drawer to support separate RFID readers to monitor the items in each drawer. The temperature-controlled drawer is insulated so that adjacent non-temperature controlled drawers are not significantly affected by the temperature of the temperature-controlled drawer and they may exist at room temperature. An automatic RFID data detection system determines the temperature requirements of medical items in the temperature-controlled drawer and controls the temperature control device to maintain the required temperature. A temperature logging system for the temperature controlled drawer is provided. A separate RFID reader determines if a temperature-controlled item has been placed in a non-temperature controlled drawer and if so, an alert is provided.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/310,569, filed Dec. 2, 2011, now U.S. Pat. No. 8,749,356; which is acontinuation-in-part of U.S. application Ser. No. 12/631,861, filed onDec. 7, 2009, now U.S. Pat. No. 8,384,545, and which also claims thebenefit of U.S. Provisional Application No. 61/419,762, filed on Dec. 3,2010, all of which are incorporated herein by reference.

BACKGROUND

The invention relates generally to the field of medicationadministration, and more particularly, to a medication administrationsystem and associated method that provide identification, tracking, andtemperature control over medications.

Medication dispensing systems have been in use for many years. Theinitial purpose of such systems was to reduce medication errorsassociated with manual distribution and the high cost of maintaining alarge amount of inventory. Current systems present many advantages,including lower costs associated with pharmaceutical distribution,improved inventory control, substance control, automated documentation,further reduction of errors, and relieving professional pharmacists andnursing personnel of many tasks.

In large medical facilities, the main inventories of pharmaceuticalitems are held in storage locations which are often far removed from thepatients who use them. To facilitate secure and accurate delivery of thepharmaceutical items from these storage locations to the patient, avariety of systems have been proposed and put into use. In earliersystems, referred to as a “cart exchange” system, medication carts aredistributed at nursing stations in the medical facility, remote from thecentral pharmacy, and are periodically exchanged with fully suppliedcarts. Typically these carts contain a twenty-four hour supply ofmedications sorted by patient into specific drawers. The “used” cart isreturned to a central pharmacy of supply area where the next twenty-fourhours of medications are replenished. Narcotics, are stored in lockedboxes on the floor, requiring two nurses with separate keys and awritten log.

While the cart exchange system is still in use for some medications, theactivities of bringing up many new orders from the central pharmacyduring the day, and having a large amount of unused medication beingreturned results in a large amount of labor. The re-stocking of thesemedications needs to be done accurately, and is very time consuming. Asa result there has been an increasing use of automated, processor-based,medication cabinets on the nursing floors. The processor on each cabinetmonitors the access to the pharmaceutical items in these fixed cabinets,allowing the current on-hand inventory and the need for replenishment tobe communicated to a central processor at the central pharmacy location.These processor-based dispensing cabinets were initially used for themore convenient management of narcotics, and for the ability to have a“floor stock” of common medications from which a nurse could issue thefirst dose of a needed new prescription, while waiting for thetwenty-four hours supply to be delivered from the pharmacy in theexchange cart, or on a special order basis.

Referring now to FIG. 23 the medication cabinet 300 typically comprisesan integrated touch screen 304 coupled to a control unit 306, acommunication link 308 for linking to a central server 310, and acommunication link 314 for linking to one or more carts 316. Suchcommunication links 308 and 314 are schematically shown as connectionsfor wired communication, but could also be transmitters and receivers(e.g., RF, IR, acoustical) for wireless communication as would berecognized by one of ordinary skill in communication technologies. Inaddition to the data that is input via the communication links 308 and314, data is input manually via a virtual keyboard included in the touchscreen 304. The communication link 308 is a connection to the server 310and allows the medication cabinet 300 to interface with the data base320 to which the server 310 has access for real-time updates, as needed.It also provides necessary information to guide the pre-authorizedhealthcare attendant in the preparation of patient medications,intravenous solutions, and the like. In an alternative embodiment shownin FIG. 24, an actual keyboard 322 or keypad, or similar device, mayreplace or augment the functions of the touch screen 304.

These processor-based medication cabinets 300 offer the possibility ofstoring the majority of medications that the patients on the floor mightneed during the day and night. In many cases, these medications arestored in pockets within locked drawers. A nurse, upon entering his orher own personal ID, and the ID of a specific patient, will see themedications that are approved overall for that selected patient and willalso see what medications are due at that particular time, referred togenerally as “Due Medications.” The task for the central pharmacy thenis to monitor the on-hand stock of the medications stored in thecabinets, and restock those levels at regular intervals. A significantadvantage of this process is not having unused doses of medicationsreturned to the central pharmacy. It also means that first doses (aswell as subsequent doses) are immediately available.

There are still many situations that continue to require medications tobe brought from the central pharmacy. For example, to avoid medicationerrors, intravenous fluids (IVs) that contain medication may be mixed inthe pharmacy and brought up to the floor for safety reasons, rather thanbeing prepared by nurses by attaching a so-called piggy-back medicationbag to a standard diluent bag. There are also specialized, orinfrequently-used medications, or those with short life, or requiringrefrigeration, or that need special handling from the pharmacy. Manymedicines and vaccines are temperature sensitive and have precisestorage requirements. Some medical compositions having low stabilityneed to be maintained under low temperature, perhaps within the range of2 to 6 degrees Celsius. Typically where cooling is required, a separatemedication cabinet is used that includes a refrigeration unit.

Present medication cabinets are either entirely refrigerated ornon-refrigerated. Every drawer in these cabinets experiences the samerefrigeration, or lack thereof, depending on the cabinet. Refrigerationis relatively expensive due to the power requirements and therefrigeration devices needed. Medication cabinets as a whole areexpensive and relatively large, each having its own computer equipment,power equipment, communication equipment, and each taking up valuablefloor space. In many cases in the prior art where some patients requiremedications that must be refrigerated prior to administration, as wellas medications that should not be refrigerated, two cabinets arerequired, one of which is refrigerated and the other of which isnon-refrigerated. In some cases, only a small portion of a refrigeratedcabinet is needed yet refrigeration is provided to the entire cabinet, alarge portion of which is empty. This is an inefficient approach. Whilethe current systems provide working methods for issuing refrigeratedmedications, it would be desirable to reduce the cost of the cabinetdrawers, allowing more items to be kept in a single cabinet that hasboth refrigerated and non-refrigerated drawers. It would therefore bebeneficial from both a cost standpoint and a space standpoint to haveboth refrigerated and non-refrigerated drawers in a single cabinet.

It is also desirable to be able to track the temperature of therefrigerator or other temperature-controlled cabinet or drawer andrecord the tracked temperature over time in a log. Such tracking andrecord keeping may be strongly recommended or required by somehealthcare organizations, such as the Joint Commission on Accreditationof Healthcare Organizations (JCAHO). It is also desirable to be able toautomatically provide an alert if the temperature (or relative humidity)is outside an acceptable range for the medications requiring temperaturecontrol.

The handling of temperature controlled medications has also been amanual process in determining which medication requires temperaturecontrol and under what conditions it must be stored. Such manualhandling, examination, and research is time consuming. It would bedesirable to provide a system and method that can automate at least someof these requirements so that efficiency is increased.

Hence, those skilled in the art have recognized a need for and automatedsystem and method for recognizing which medications requirerefrigeration, determining what level of refrigeration is required, andeffecting such refrigeration. Those of skill in the art have alsorecognized the need to track the temperature of the refrigerator orother temperature-controlled cabinet or drawer in whichtemperature-controlled medications are kept and record the trackedtemperature over time in a log. Those of skill in the art have furtherrecognized the need for having both refrigerated and non-refrigerateddrawers in a single cabinet so that expense and requirements for spaceare both reduced. The present invention fulfills these needs and others.

Radio-frequency identification (“RFID”) is the use of electromagneticenergy (“EM energy”) to stimulate a responsive device (known as an RFID“tag” or transponder) to identify itself and in some cases, provideadditionally stored data. RFID tags typically include a semiconductordevice having a memory, circuitry, and one or more conductive tracesthat form an antenna. Typically, RFID tags act as transponders,providing information stored in the semiconductor device memory inresponse to an RF interrogation signal received from a reader, alsoreferred to as an interrogator. Some RFID tags include securitymeasures, such as passwords and/or encryption. Many RFID tags alsopermit information to be written or stored in the semiconductor memoryvia an RF signal.

RFID tags may be incorporated into or attached to articles to betracked. In some cases, the tag may be attached to the outside of anarticle with adhesive, tape, or other means and in other cases, the tagmay be inserted within the article, such as being included in thepackaging, located within the container of the article, or sewn into agarment. The RFID tags are manufactured with a unique identificationnumber which is typically a simple serial number of a few bytes with acheck digit attached. This identification number is incorporated intothe tag during manufacture. The user cannot alter thisserial/identification number and manufacturers guarantee that eachserial number is used only once. This configuration represents the lowcost end of the technology in that the RFID tag is read-only and itresponds to an interrogation signal only with its identification number.Typically, the tag continuously responds with its identification number.Data transmission to the tag is not possible. These tags are very lowcost and are produced in enormous quantities.

Such read-only RFID tags typically are permanently attached to anarticle to be tracked and, once attached, the serial number of the tagis associated with its host article in a computer data base. Forexample, a particular type of medicine may be contained in hundreds orthousands of small vials. Upon manufacture, or receipt of the vials at ahealth care institution, an RFID tag is attached to each vial. Each vialwith its permanently attached RFID tag will be checked into the database of the health care institution upon receipt. The RFIDidentification number may be associated in the data base with the typeof medicine, size of the dose in the vial, and perhaps other informationsuch as the expiration date of the medicine. Thereafter, when the RFIDtag of a vial is interrogated and its identification number read, thedata base of the health care institution can match that identificationnumber with its stored data about the vial. The contents of the vial canthen be determined as well as any other characteristics that have beenstored in the data base. This system requires that the institutionmaintain a comprehensive data base regarding the articles in inventoryrather than incorporating such data into an RFID tag.

An object of the tag is to associate it with an article throughout thearticle's life in a particular facility, such as a manufacturingfacility, a transport vehicle, a health care facility, a storage area,or other, so that the article may be located, identified, and tracked,as it is moved. For example, knowing where certain medical articlesreside at all times in a health care facility can greatly facilitatelocating needed medical supplies when emergencies arise. Similarly,tracking the articles through the facility can assist in generating moreefficient dispensing and inventory control systems as well as improvingwork flow in a facility. Additionally, expiration dates can be monitoredand those articles that are older and about to expire can be moved tothe front of the line for immediate dispensing. This results in betterinventory control and lowered costs.

Other RFID tags are writable and information about the article to whichthe RFID tag is attached can be programmed into the individual tag.While this can provide a distinct advantage when a facility's computerservers are unavailable, such tags cost more, depending on the size ofthe memory in the tag. Programming each one of the tags with informationcontained in the article to which they are attached involves furtherexpense.

RFID tags may be applied to containers or articles to be tracked by themanufacturer, the receiving party, or others. In some cases where amanufacturer applies the tags to the product, the manufacturer will alsosupply a respective data base file that links the identification numberof each of the tags to the contents of each respective article. Thatmanufacturer supplied data base can be distributed to the customer inthe form of a file that may easily be imported into the customer'soverall data base thereby saving the customer from the expense ofcreating the data base.

Many RFID tags used today are passive in that they do not have a batteryor other autonomous power supply and instead, must rely on theinterrogating energy provided by an RFID reader to provide power toactivate the tag. Passive RFID tags require an electromagnetic field ofenergy of a certain frequency range and certain minimum intensity inorder to achieve activation of the tag and transmission of its storeddata. Another choice is an active RFID tag; however, such tags requirean accompanying battery to provide power to activate the tag, thusincreasing the expense of the tag and making them undesirable for use ina large number of applications.

Depending on the requirements of the RFID tag application, such as thephysical size of the articles to be identified, their location, and theability to reach them easily, tags may need to be read from a shortdistance or a long distance by an RFID reader. Such distances may varyfrom a few centimeters to ten or more meters. Additionally, in the U.S.and in other countries, the frequency range within which such tags arepermitted to operate is limited. As an example, lower frequency bands,such as 125 KHz and 13.56 MHz, may be used for RFID tags in someapplications. At this frequency range, the electromagnetic energy isless affected by liquids and other dielectric materials, but suffersfrom the limitation of a short interrogating distance. At higherfrequency bands where RFID use is permitted, such as 915 MHz and 2.4GHz, the RFID tags can be interrogated at longer distances, but theyde-tune more rapidly as the material to which the tag is attachedvaries. It has also been found that at these higher frequencies, closelyspaced RFID tags will de-tune each other as the spacing between tags isdecreased.

There are a number of common situations where the RFID tags may belocated inside enclosures. Some of these enclosures may have entirely orpartially metal or metallized surfaces. Examples of enclosures includemetal enclosures (e.g., shipping containers), partial metal enclosures(e.g., vehicles such as airplanes, buses, trains, and ships that have ahousing made from a combination of metal and other materials), andnon-metal enclosures (e.g., warehouses and buildings made of wood).Examples of objects with RFID tags that may be located in theseenclosures include loose articles, packaged articles, parcels insidewarehouses, inventory items inside buildings, various goods insideretail stores, and various portable items (e.g., passengeridentification cards and tickets, baggage, cargo, individual life-savingequipment such as life jackets and masks) inside vehicles, etc.

The read range (i.e., the range of the interrogation and/or responsesignals) of RFID tags is limited. For example, some types of passiveRFID tags have a maximum range of about twelve meters, which may beattained only in ideal free space conditions with favorable antennaorientation. In a real situation, the observed tag range is often sixmeters or less. Therefore, some of the enclosures described above mayhave dimensions that far exceed the read range of an individual RFIDtag. Unless the RFID reader can be placed in close proximity to a targetRFID tag in such an enclosure, the tag will not be activated and read.Additionally, metal surfaces of the enclosures present a seriousobstacle for the RF signals that need to be exchanged between RFIDreaders and RFID tags, making RFID tags located behind those metalsurfaces difficult or impossible to detect.

In addition to the above, the detection range of the RFID systems istypically limited by signal strength to short ranges, frequently lessthan about thirty centimeters for 13.56 MHz systems. Therefore, portablereader units may need to be moved past a group of tagged items in orderto detect all the tagged items, particularly where the tagged items arestored in a space significantly greater than the detection range of astationary or fixed single reader antenna. Alternately, a large readerantenna with sufficient power and range to detect a larger number oftagged items may be used. However, such an antenna may be unwieldy andmay increase the range of the radiated power beyond allowable limits.Furthermore, these reader antennae are often located in stores or otherlocations where space is at a premium and it is expensive andinconvenient to use such large reader antennae. In another possiblesolution, multiple small antennae may be used but such a configurationmay be awkward to set up when space is at a premium and when wiring ispreferred or required to be hidden.

In the case of medical supplies and devices, it is desirable to developaccurate tracking, inventory control systems, and dispensing systems sothat RFID tagged devices and articles may be located quickly should theneed arise, and may be identified for other purposes, such as expirationdates. In the case of medical supply or dispensing cabinets used in ahealth care facility, a large number of medical devices and articles arelocated closely together, such as in a plurality of drawers. Cabinetssuch as these are typically made of metal, which can make the use of anexternal RFID system for identification of the stored articlesdifficult. In some cases, such cabinets are locked due to the presenceof narcotics or other medical articles or apparatus within them that aresubject to a high theft rate. Thus, manual identification of the cabinetcontents is difficult due to the need to control access.

Providing an internal RFID system in such a cabinet can pose challenges.Where internal articles can have random placement within the cabinet,the RFID system must be such that there are no “dead zones” that theRFID system is unable to reach. In general, dead zones are areas inwhich the level of coupling between an RFID reader antenna and an RFIDtag is not adequate for the system to perform a successful read of thetag. The existence of such dead zones may be caused by orientations inwhich the tag and the reader antennae are in orthogonal planes. Thus,articles placed in dead zones may not be detected thereby resulting ininaccurate tracking of tagged articles.

Often in the medical field, there is a need to read a large number oftags attached to articles in such an enclosure, and as mentioned above,such enclosures have limited access due to security reasons. Thephysical dimension of the enclosure may need to vary to accommodate alarge number of articles or articles of different sizes and shapes. Inorder to obtain an accurate identification and count of suchclosely-located medical articles or devices, a robust electromagneticenergy field must be provided at the appropriate frequency within theenclosure to surround all such stored articles and devices to be surethat their tags are all are activated and read. Such medical devices mayhave the RFID tags attached to the outside of their containers and maybe stored in various orientations with the RFID tag (and associatedantenna) pointed upwards, sideways, downward, or at some other angle ina random pattern.

Generating such a robust EM energy field is not an easy task. Where theenclosure has a size that is resonant at the frequency of operation, itcan be easier to generate a robust EM field since a resonant standingwave may be generated within the enclosure. However, in the RFID fieldthe usable frequencies of operation are strictly controlled and arelimited. It has been found that enclosures are desired for the storageof certain articles that do not have a resonant frequency that matchesone of the allowed RFID frequencies. Thus, a robust EM field must beestablished in another way.

Additionally, where EM energy is introduced to such an enclosure forreading the RFID tags within, efficient energy transfer is ofimportance. Under static conditions, the input or injection of EM energyinto an enclosure can be maximized with a simple impedance matchingcircuit positioned between the conductor delivering the energy and theenclosure. As is well known to those of skill in the art, such impedancematching circuits or devices maximize the power transfer to theenclosure while minimizing the reflections of power from the enclosure.Where the enclosure impedance changes due to the introduction or removalof articles to or from the enclosure, a static impedance matchingcircuit may not provide optimum energy transfer into the enclosure. Ifthe energy transfer and resulting RF field intensity within theenclosure were to fall below a threshold level, some or many of the tagson articles within the enclosure would not be activated to identifythemselves, leaving an ineffective inventory system.

It is a goal of many health care facilities to keep the use of EM energyto a minimum, or at least contained. The use of high-power readers tolocate and extract data from RFID tags is generally undesirable inhealth care facilities, although it may be acceptable in warehouses thatare sparsely populated with workers, or in aircraft cargo holds.Radiating a broad beam of EM energy at a large area, where that EMenergy may stray into adjacent, more sensitive areas, is undesirable.Efficiency in operating a reader to obtain the needed identificationinformation from tags is an objective. In many cases where RFID tags areread, hand-held readers are used. Such readers transmit a relativelywide beam of energy to reach all RFID tags in a particular location.While the end result of activating each tag and reading it may beaccomplished, the transmission of the energy is not controlled except bythe aim of the user. Additionally, this is a manual system that willrequire the services of one or more individuals, which can also beundesirable in facilities where staff is limited

Hence, those of skill in the art have recognized a need for a medicationcabinet that provides both a refrigerated drawer and a non-refrigerateddrawer to reduce costs and space requirements and accommodate varioustypes of medications. A need has also been recognized for an RFID tagreader system in which the efficient use of energy is made to activateand read all RFID tags in an enclosed area. A further need forestablishing a robust EM field in enclosures to activate and read tagsdisposed at random orientations has also been recognized. A further needhas been recognized for an automated system to identify articles storedin a metal cabinet without the need to gain access to the cabinet. Thepresent invention fulfills these needs and others.

SUMMARY OF THE INVENTION

Briefly and in general terms, the present invention is directed to asystem for providing both refrigerated and non-refrigerated drawers in asingle medication cabinet with the use of RFID to identify and trackmedical articles. In particular, there is provided a cabinet for storingmedical articles, comprising a frame having a plurality of openings forreceiving drawers, the frame providing an electrically conductive cageabout a first opening to receive a first drawer, the cage having a frontlocate at the opening and a rear, a plurality of drawers, each of whichis configured to be received by a respective opening and is movable intoand out of the respective opening with the first drawer being configuredto be received by the opening having the cage, a thermoelectric cooling(“TEC”) device configured to provide cooling for a single drawer, asecond opening adjacent the first opening having no cooling device,insulation disposed between the first and second openings configured toinhibit cooling from the thermoelectric cooling device from reaching thedrawer of the second opening, and an RFID reader disposed within thecabinet and configured to read data from an RFID tag located within thecabinet.

In accordance with more detailed features, the TEC device is mounted tothe frame such that the respective drawer moves toward it when thedrawer is moved to the closed position and moves away from it when thedrawer is moved to the open position. The respective TEC drawer includesa TEC device enclosure formed at a rear portion of the drawer,configured to receive the TEC device into the enclosure when the draweris in the closed position, whereby the depth of the cabinet is reduced.The TEC device enclosure comprises a cooling diffuser configured toassist in circulating cooling equally throughout the drawer from the TECdevice. Also, the drawer having the TEC device enclosure furtherincludes partitions configured to separate medical articles from oneanother when stored in the drawer, the partitions also configured suchthat cooling from the TEC device is not inhibited from circulatingequally throughout the drawer by the partitions.

In other detailed aspects, the RFID reader comprises an antenna thatprotrudes into the drawer, a drawer includes a TEC enclosure forreceiving the TEC device when the drawer is in the closed position, theenclosure located so as to not interfere with the operation of theantenna in reading tagged articles located in the drawer. The firstdrawer is slidable into and out of the first opening of the cabinet, thedrawer having a front panel that is electrically conductive and thatcontacts the electrically conductive cage at the first opening when thedrawer is slid to a predetermined position within the cabinet. A portionof the first drawer is formed of electrically conductive material whichis located at a position on the drawer such it comes into contact withthe electrically conductive cage to thereby close an electricallyconductive cage about the drawer.

In yet another aspect in accordance with the invention, the RFID readeris configured and positioned within the cabinet to force a resonance ina drawer to result in a robust electromagnetic field for reading taggedmedical articles stored in the drawer.

Other detailed aspects include the first drawer being non-electricallyconductive except for the portion of the drawer that contacts the cageto close the cage about the drawer. And further, a temperature sensor isdisposed so as to measure the temperature in a drawer.

The features and advantages of the invention will be more readilyunderstood from the following detailed description that should be readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a drawer that may be positioned withina medical dispensing cabinet, showing the storage of a plurality ofmedical articles randomly positioned in the drawer, each of thosearticles having an integral RFID tag oriented randomly;

FIG. 2 is a perspective view of a medication dispensing cabinet havingfive drawers, one of which is similar to the schematic view of FIG. 1,the cabinet also having an integral computer for controlling access tothe cabinet and performing inventory tracking by periodically readingany RFID tags placed on articles stored within the cabinet, and forreporting the identified articles to a remote computer;

FIG. 3 is a block and flow diagram showing an embodiment in which anRFID reader transmits activating EM energy into a drawer containing RFIDtags with a single transmitting antenna, receives the data output fromthe activated RFID tags with a single receiving antenna, a computercontrolling the transmission of activating energy and receiving the datafrom the activated RFID tags for processing;

FIG. 4 is a block and flow diagram similar to FIG. 3 showing anembodiment in which an RFID reader transmits activating EM energy into adrawer containing RFID tags with two transmitting antennae, receives thedata output from the activated RFID tags with three receiving antennae,and as in FIG. 3, a computer controlling the transmission of activatingenergy and receiving the data from the activated RFID tags forprocessing;

FIG. 5 shows an enclosure with a single probe and a connector, the probebeing configured to inject EM energy into the enclosure and excite a TEmode;

FIG. 6 shows an enclosure with a single probe and a connector, the probebeing configured to inject EM energy into the enclosure and excite a TMmode;

FIG. 7 shows a plot of coupled power in an enclosure as a function offrequency for a resonant enclosure where F_(n) is the natural resonancefrequency of the enclosure;

FIG. 8 shows a plot of coupled power (ordinate axis) in an enclosure asa function of frequency (abscissa axis), where f_(f) is a forcedresonance frequency, or otherwise referred to as a frequency that is notequal to the resonant frequency of the enclosure, and f_(n) is thenatural resonant frequency of the enclosure, showing the establishmentof a robust field of coupled power in the enclosure at the f_(f)frequency;

FIG. 9 shows an enclosure with two probes each with a connector forinjecting EM energy into the enclosure, one probe being a TM probe andthe other being a TE probe;

FIG. 10 shows a probe, a connector, and an attenuator that is used toimprove the impedance match between the probe and the enclosure;

FIG. 11 shows a probe, a connector, and a passive matching circuit thatis used to improve the impedance match between the probe and enclosure;

FIG. 12 shows an active matching circuit connected between a probelocated in an enclosure and a transceiver, the active matching circuitcomprising a tunable capacitor, a dual-directional coupler, multiplepower sensors, and a comparator used to provide a closed-loop, variablematching circuit to improve the impedance match between the probe andthe enclosure;

FIG. 13 provides a side cross-sectional view of the cabinet of FIG. 2 atthe location of a drawer with the drawer removed for clarity, showingthe placement of two probe antennae in a “ceiling mount” configurationfor establishing a robust EM field in the drawer when it is in place inthe cabinet in the closed position;

FIG. 14 is a perspective view of the metallic enclosure showing theprobe configuration of FIG. 13 again showing the two probe antennae forestablishing a robust EM field in a drawer to be inserted;

FIG. 15 is a cutaway perspective side view of the metallic enclosure orframe in which are mounted the dual probe antennae of FIGS. 13 and 14with the drawer removed for clarity;

FIG. 16 is a frontal perspective view of the view of FIG. 14 with acutaway plastic drawer in place in the metallic enclosure and furthershowing the dual ceiling mount probe antennae protected by anelectromagnetically inert protective cover, and further showing coolingsystem components mounted at the back of the cabinet near the drawer'sback, the drawing also showing a partial view of a drawer slidemechanism for ease in sliding the drawer between open and closedpositions in the cabinet, the drawer front and rear panels having beencutaway in this view;

FIG. 17 is a frontal perspective view at the opposite angle from that ofFIG. 16 with the plastic drawer completely removed showing the dualceiling mount probe antennae protected by the EM inert protective covermounted to the metallic enclosure, and further showing the coolingsystem components of FIG. 16 mounted at the back of the cabinet as aspring loading feature to automatically push the drawer to the openposition when the drawer's latch is released, the figure also showing amounting rail for receiving the slid of the drawer;

FIG. 18 is a schematic view with measurements in inches of the placementof two TE₀₁ mode probes in the top surface of the enclosure shown inFIGS. 13-15;

FIG. 19 is a schematic view of the size and placement within the drawerof FIG. 16 of two microstrip or “patch” antennae and their microstripconductors disposed between respective antennae and the back of thedrawer at which they will be connected to SMA connectors in oneembodiment, for interconnection with other components;

FIG. 20 is diagram of field strength in an embodiment of an enclosurewith a probe placed in the enclosure at a position in accordance withthe diagram of FIG. 19;

FIG. 21 is a lower scale drawing of the field intensity diagram of FIG.20 showing a clearer view of the field intensity nearer the front andback walls of the enclosure;

FIGS. 22A and 22B together present a block electrical and signal diagramfor a multiple-drawer medical cabinet, such as that shown in FIG. 2,showing the individual multiplexer switches, the single RFID scanner,and power control;

FIG. 23 shows a medication administration cabinet having a control unit,a plurality of drawers and connections to a server and data base;

FIG. 24 shows the medication administration cabinet of FIG. 23 with aview of two input devices, one of which is a keyboard and the other ofwhich is a pointing device in the form of a “mouse;”

FIG. 25 is an exploded view of a drawer removed from the opening andFaraday cage of the medication cabinet, showing details of the drawerdesign including partitions for creating pockets to store medical items,a TEC enclosure at the rear of the drawer, and part of the Faraday cagecreated in the cabinet;

FIG. 26, is an enlarged view of the drawer of FIG. 25 looking frombehind the drawer so that the metallic front of the drawer can be seen,which, when the drawer is in the closed position, completes the Faradaycage about the drawer so that the RFID system will operate effectively;

FIG. 27 is another view of the drawer of FIG. 25 showing the TEC deviceenclosure in greater detail at the back of the drawer, showing thethermal diffuser formed into the enclosure;

FIG. 28 is a more detailed view of the construction of the part of thecabinet surrounding a refrigerated drawer showing slabs of insulationaround the top, bottom, and sides of the drawer, and the metallic linerfor forming the Faraday cage;

FIG. 29 presets a partial view of the front of the drawer showing theinsertion of insulation in the front panel of the drawer;

FIG. 30 presents a perspective view of a system in accordance withaspects of the invention showing an open refrigerated drawer with amounted TEC device, mediations in pockets of the drawer, threetemperature sensors in pockets, and ambient temperature sensor, controlunit, and connection with a server and data base;

FIG. 31 presents a method in accordance with aspects of the inventionproviding an automatic system for detecting temperature controlledmedications, determining the temperature requirements for thosemedications, and controlling the TEC device to maintain the requiredtemperature, with the figure also showing a temperature data loggingsystem to satisfy requirements imposed by healthcare authorities; and

FIG. 32 is a block diagram of a system in accordance with aspects of theinvention in which an RFID detector system detects the presence oftemperature controlled medical items, notifies a processor whichidentifies the temperature requirement for the detected medication, andcontrols the TEC device in a drawer to maintain the requiredtemperature, the processor also programmed to create a log oftemperature events while the medication is in the cabinet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now in more detail to the exemplary drawings for purposes ofillustrating embodiments of the invention, wherein like referencenumerals designate corresponding or like elements among the severalviews, there is shown in FIG. 1 a schematic representation of a partialenclosure 20 in which a plurality of medical articles 22 are stored,each with a respective RFID tag 24 that has a unique identificationnumber. The partial enclosure may comprise a drawer having a front 26, aleft side 28, a right side 30, a rear 32, and a bottom 34. Thesearticles are randomly distributed in the drawer with the RFID tagsfacing in various and random directions.

As used in regard to the embodiments herein, “reader” and “interrogator”refer to a device that may read or write/read. The data capture deviceis always referred to as a reader or an interrogator regardless ofwhether it can only read or is also capable of writing. A readertypically contains a radio frequency module (a transmitter and areceiver, sometimes referred to as a “transceiver”), a control unit anda coupling element (such as an antenna or antennae) to the RFID tag.Additionally, many readers include an interface for forwarding dataelsewhere, such as an RS-232 interface. The reader, when transmitting,has an interrogation zone within which an RFID tag will be activated.When within the interrogation zone, the RFID tag will draw its powerfrom the electrical/magnetic field created in the interrogation zone bythe reader. In a sequential RFID system (SEQ), the interrogation fieldis switched off at regular intervals. The RFID tag is programmed torecognize these “off” gaps and they are used by the tag to send data,such as the tag's unique identification number. In some systems, thetag's data record contains a unique serial number that is incorporatedwhen the tag is manufactured and which cannot be changed. This numbermay be associated in a data base with a particular article when the tagis attached to that article. Thus, determining the location of the tagwill then result in determining the location of the article to which itis attached. In other systems, the RFID tag may contain more informationabout the article to which it is attached, such as the name oridentification of the article, its expiration date, it dose, the patientname, and other information. The RFID tag may also be writable so thatit can be updated.

As used in regard to the embodiments herein, “tag” is meant to refer toan RFID transponder. Such tags typically have a coupling element, suchas an antenna, and an electronic microchip. The microchip includes datastorage, also referred to as memory.

FIG. 2 presents a representative medical dispensing cabinet 40comprising a plurality of movable drawers 42. In this embodiment, thereare five drawers that slide outwardly from the cabinet so that access isprovided to the contents of the drawers. FIG. 1 is a schematic diagramof a representative drawer that may be positioned within the cabinet ofFIG. 2 for sliding outward to provide access to the drawer's contentsand for sliding inward into the cabinet to secure the drawer's contents.The cabinet also comprises an integral computer 44 that may be used tocontrol access to the drawers and to generate data concerning access andcontents, and to communicate with other systems. In this embodiment, thecomputer generates data concerning the number and type of articles inthe drawers, the names of the patients for whom they have beenprescribed, the prescribed medications and their prescribedadministration dates and times, as well as other information. In asimpler system, the computer may simply receive unique identificationnumbers from stored articles and pass those identification numbers to aninventory control computer that has access to a data base for matchingthe identification numbers to article descriptions.

Such a cabinet may be located at a nursing station on a particular floorof a health care institution and may contain the prescriptions for thepatients of that floor. As prescriptions are prepared for the patientsof that floor, they are delivered and placed into the cabinet 40. Theyare logged into the integral computer 44, which may notify the pharmacyof their receipt. A drawer may also contain non-prescription medicalsupplies or articles for dispensing to the patients as determined by thenursing staff. At the appropriate time, a nurse would access the drawerin which the medical articles are stored through the use of the computer44, remove a particular patient's prescriptions and any needednon-prescription articles, and then close the drawer so that it issecured. In order to access the cabinet, the nurse may need to providevarious information and may need a secure access code. The drawers 42may be locked or unlocked as conditions require.

The computer 44 in some cases may be in communication with otherfacilities of the institution. For example, the computer 44 may notifythe pharmacy of the health care institution that a patient'sprescription has been removed from the cabinet for administration at aparticular day and time. The computer may also notify the financedepartment of the health care institution of the removal ofprescriptions and other medical articles for administration to aparticular patient. This medication may then be applied to the patient'saccount. Further, the computer 44 may communicate to administration forthe purpose of updating a patient's Medication Administration Record(MAR), or e-MAR. The medication cabinet 40 computer 44 may be wirelesslyconnected to other computers of the health care institution or may havea wired connection. The cabinet may be mounted on wheels and may bemoved about as needed or may be stationary and unable to move.

Systems that use RFID tags often employ an RFID reader in communicationwith one or more host computing systems that act as depositories tostore, process, and share data collected by the RFID reader. Turning nowto FIGS. 3 and 4, a system and method 50 for tracking articles are shownin which a drawer 20 of the cabinet 40 of FIG. 2 is monitored to obtaindata from RFID tags disposed with articles in that drawer. As mentionedabove, a robust field of EM energy needs to be established in thestorage site so that the RFID tags mounted to the various storedarticles will be activated, regardless of their orientation.

In FIGS. 3 and 4, the tracking system 50 is shown for identifyingarticles in an enclosure and comprises a transmitter 52 of EM energy aspart of an RFID reader. The transmitter 52 has a particular frequency,such as 915 MHz, for transmitting EM energy into a drawer 20 by means ofa transmitting antenna 54. The transmitter 52 is configured to transmitthe necessary RFID EM energy and any necessary timing pulses and datainto the enclosure 20 in which the RFID tags are disposed. In this case,the enclosure is a drawer 20. The computer 44 of an RFID reader 51controls the EM transmitter 52 to cycle between a transmit period and anon-transmit, or off, period. During the transmit period, thetransmitted EM energy at or above a threshold intensity level surroundsthe RFID tags in the drawer thereby activating them. The transmitter 52is then switched to the off period during which the RFID tags respondwith their respective stored data.

The embodiment of FIG. 3 comprises a single transmitting probe antenna54 and a single receiving antenna 56 oriented in such a manner so as tooptimally read the data transmitted by the activated RFID tags locatedinside the drawer 20. The single receiving antenna 56 is communicativelycoupled to the computer 44 of the reader 50 located on the outside ofthe drawer 20 or on the inner bottom of the drawer. Other mountinglocations are possible. Coaxial cables 58 or other suitable signal linkscan be used to couple the receiving antenna 56 to the computer 44. Awireless link may be used in a different embodiment. Although not shownin the figures, those skilled in the art will recognize that variousadditional circuits and devices are used to separate the digital datafrom the RF energy, for use by the computer. Such circuits and deviceshave not been shown in FIGS. 3 and 4 to avoid unneeded complexity in thedrawing.

The embodiment of FIG. 4 is similar to the embodiment of FIG. 3 butinstead uses two transmitting probe antennae 60 and 62 and threereceiving antennae 64, 66, and 68. The configuration and the number oftransmitting probe antennae and receiving antennae to be used for asystem may vary based at least in part on the size of the enclosure 20,the frequency of operation, the relationship between the operationfrequency and the natural resonance frequency of the enclosure, and theexpected number of RFID tags to be placed in it, so that all of the RFIDtags inside the enclosure can be reliably activated and read. Thelocation and number of RFID reader components can be dependent on theparticular application. For example, fewer components may be requiredfor enclosures having a relatively small size, while additionalcomponents, such as shown in FIG. 4, may be needed for largerenclosures. Although shown in block form in FIGS. 3 and 4, it should berecognized that each receiving antenna 56, 64, 66, and 68 of the system50 may comprise a sub-array in a different embodiment.

The transmit antennae (54, 60, and 62) and the receive antennae (56, 64,66, and 68) may take different forms. In one embodiment as is discussedin more detail below, a plurality of “patch” or microstrip antennae wereused as the reader receiving antennae and were located at positionsadjacent various portions of the bottom of the drawer while the transmitantennae were wire probes located at positions adjacent portions of thetop of the drawer. It should be noted that in the embodiments of FIGS. 3and 4, the RFID reader 50 may be permanently mounted in the same cabinetat a strategic position in relation to the drawer 20.

One solution for reliably interrogating densely packed or randomlyoriented RFID tags in an enclosure is to treat the enclosure as aresonant cavity. Establishing a resonance within the cavity enclosurecan result in a robust electromagnetic field capable of activating allRFID tags in the enclosure. This can be performed by building anenclosure out of electrically conductive walls and exciting the metallicenclosure, or cavity, using a probe or probes to excite transverseelectric (TE) or transverse magnetic (TM) fields in the cavity at thenatural frequency of resonance of the cavity. This technique will workif the cavity dimensions can be specifically chosen to set up theresonance at the frequency of operation or if the frequency of operationcan be chosen for the specific enclosure size. Since there are limitedfrequency bands available for use in RFID applications, varying the RFIDfrequency is not an option for many applications. Conversely, requiringa specific set of physical dimensions for the enclosure so that thenatural resonant frequency of the enclosure will equal the availableRFID tag activating frequency will restrict the use of this techniquefor applications where the enclosure needs to be of a specific size.This latter approach is not practical in view of the many differentsizes, shapes, and quantities of medical articles that must be stored.

Referring now to FIG. 5, a rectangular enclosure 80 is provided that maybe formed as part of a medical cabinet, such as the cabinet shown inFIG. 2. It may be embodied as a frame disposed about a non-metallicdrawer in such a cabinet. The enclosure 80 is formed of metallic ormetallized walls 82, floor 83, and ceiling 84 surfaces, all of which areelectrically conductive. All of the walls 82, floor 83, and ceiling 84may also be referred to herein as “walls” of the enclosure. FIG. 5 alsoshows the use of an energy coupling or probe 86 located at the topsurface 84 of the enclosure 80. In this embodiment, the probe takes theform of a capacitor probe 88 in that the probe 88 has a first portion 94that proceeds axially through a hole 90 in the ceiling 84 of theenclosure. The purpose of the coupling is to efficiently transfer theenergy from the source 52 (see FIGS. 3 and 4) to the interior 96 of theenclosure 80. The size and the position of the probe are selected foreffective coupling and the probe is placed in a region of maximum fieldintensity. In FIG. 5, a TE₀₁ mode is established through the use ofcapacitive coupling. The length and distance of the bent portion 94 ofthe probe 88 affects the potential difference between the probe and theenclosure 80.

Similarly, FIG. 6 presents an inductive coupling 110 of the externalenergy to an enclosure 112. The coupling takes the form of a loop probe114 mounted through a side wall 116 of the enclosure. The purpose ofthis probe is to establish a TM₀₁ mode in the enclosure.

The rectangular enclosures 80 and 112 shown in FIGS. 5 and 6 each have anatural frequency of resonance f_(n), shown in FIG. 7 and indicated onthe abscissa axis 118 of the graph by f_(n). This is the frequency atwhich the coupled power in the enclosure is the highest, as shown on theordinate axis 119 of the graph. If the injected energy to the enclosuredoes not match the f_(n) frequency, the coupled power will not benefitfrom the resonance phenomenon of the enclosure. In cases where thefrequency of operation cannot be changed, and is other than f_(n), andthe size of the enclosure cannot be changed to obtain an f_(n) that isequal to the operating frequency, another power coupling apparatus andmethod must be used. In accordance with aspects of the invention, anapparatus and method are provided to result in a forced resonance f_(f)within the enclosure to obtain a standing wave within the enclosure withconstructive interference. Such a standing wave will establish a robustenergy field within the enclosure strong enough to activate all RFIDtags residing therein.

When an EM wave that is resonant with the enclosure enters, it bouncesback and forth within the enclosure with low loss. As more wave energyenters the enclosure, it combines with and reinforces the standing wave,increasing its intensity (constructive interference). Resonation occursat a specific frequency because the dimensions of the cavity are anintegral multiple of the wavelength at the resonance frequency. In thepresent case where the injected energy is not at the natural resonancefrequency f_(n) of the enclosure, a solution in accordance with aspectsof the invention is to set up a “forced resonance” in an enclosure. Thisforced resonance is different from the natural resonance of theenclosure in that the physical dimensions of the enclosure are not equalto an integral multiple of the wavelength of the excitation energy, asis the case with a resonant cavity. A forced resonance can be achievedby determining a probe position, along with the probe length to allowfor energy to be injected into the cavity such that constructiveinterference results and a standing wave is established. The energyinjected into the enclosure in this case will set up an oscillatoryfield region within the cavity, but will be different from a standingwave that would be present at the natural resonance frequency f_(n) of aresonant cavity. The EM field excited from this forced resonance will bedifferent than the field structure found at the natural resonance of aresonant cavity, but with proper probe placement of a probe, a robust EMfield can nevertheless be established in an enclosure for RFID taginterrogation. Such is shown in FIG. 8 where it will be noted that thecurve for the forced resonance f_(f) coupled power is close to that ofthe natural resonance f_(n).

Turning now to FIG. 9, an enclosure 120 having two energy injectionprobes is provided. The first probe 86 is capacitively coupled to theenclosure 120 in accordance with FIG. 5 to establish a TE₀₁ mode. Thesecond probe 114 is inductively coupled to the enclosure 120 inaccordance with FIG. 6 to establish a TM₀₁ mode. These two probes areboth coupled to the enclosure to inject energy at a frequency f_(f) thatis other than the natural resonance frequency f_(n) of the enclosure.The placement of these probes in relation to the ceiling 126 and walls128 of the enclosure will result in a forced resonance within theenclosure 120 that optimally couples the energy to the enclosure andestablishes a robust EM field within the enclosure for reading RFID tagsthat may be located therein. The placement of these probes in relationto the walls of the enclosure, in accordance with aspects of theinvention, result in the forced resonance curve f_(f) shown in FIG. 8.

Referring briefly to FIG. 10, an impedance matching circuit 121 is shownthat functions to match the impedance of a source of energy 122 to theenclosure 120. The impedance matching circuit is located between thecoaxial cable 122 that feeds activating energy to the enclosure 120 andthe capacitively coupled probe 88 through a hole in the metallic ceiling126 of the enclosure. While the hole is not shown in the drawing of FIG.10, the insulator 123 that electrically insulates the probe from themetallic ceiling is shown. In this case, the matching circuit 121consists of only a resistive attenuator 124 used to reduce reflectionsof energy by the enclosure 120. However, as will be appreciated by thoseof skill in the art, capacitive and inductive components are likely toexist in the enclosure and in the coupling 88. FIG. 11 on the other handpresents an impedance matching circuit 124 having passive reactivecomponents for use in matching the impedance of the coaxial cable/energysource 122 and the enclosure 120. In this exemplary impedance matchingcircuit 124, an inductive component 125 and a capacitive component 127are connected in series, although other configurations, including theaddition of a resistive component and other connection configurations,are possible.

Passive components such as resistors, inductors, and capacitors shown inFIGS. 10 and 11 can be used to form matching circuits to match theimpedances of the energy source and the enclosure. This will aid incoupling power into the enclosure. However, the passive matching circuitwill improve the impedance match for a specific enclosure loading, suchas an empty enclosure, partially loaded, or fully loaded enclosure. Butas the enclosure contents are varied, the impedance match may not beoptimized due to the variation in contents in the enclosure causing theimpedance properties of the enclosure to change.

This non-optimal impedance match caused by variation in enclosureloading can be overcome by the use of an active impedance matchingcircuit which utilizes a closed loop sensing circuit to monitor forwardand reflected power. Referring now to FIG. 12, an active matchingcircuit 130 is provided that comprises one or several fixed valuepassive components such as inductors 132, capacitors 134, or resistors(not shown). In addition, one or several variable reactance devices,such as a tunable capacitor 134, are incorporated into the circuit;these tunable devices making this an active impedance matching circuit.The tunable capacitor 134 can take the form of a varactor diode,switched capacitor assembly, MEMS capacitor, or BST (Barium StrontiumTitanate) capacitor. A control voltage is applied to the tunablecapacitor 134 and varied to vary the capacitance provide by the device.The tunable capacitor 134 provides the capability to actively change theimpedance match between the probe 140 and the enclosure 142.

To complete the active matching circuit, a dual directional coupler 144along with two power sensors 146 can be incorporated. The dualdirectional coupler 144 and the power sensors 146 provide the ability tosense forward and reflected power between the RFID transceiver 148 andthe active matching circuit 130 and enclosure 142. Continuous monitoringof the ratio of forward and reflected power by a comparator 150 providesa metric to use to adjust the tunable capacitor 134 to keep the probe140 impedance matched to the enclosure 142. An ability to continuouslymonitor and improve the impedance match as the contents of the enclosureare varied is provided with the active matching circuit 130.

Referring now to the side cross-sectional view of FIG. 13, twoceiling-mounted 160 probe antennae 162 and 164 are shown mounted withinan enclosure, which may also be referred to herein as a cavity 166,which in this embodiment, operates as a Faraday cage. As shown, theFaraday cage 166 comprises walls (one of which is shown) 168, a back170, a floor 172, a ceiling 160, and a front 161 (only the position ofthe front wall is shown). All surfaces forming the cavity areelectrically conductive, are electrically connected with one another,and are structurally formed to be able to conduct the frequency ofenergy f_(f) injected by the two probes 162 and 164. In this embodiment,the cavity 166 is constructed as a metal frame 167 that may form a partof a medical supply cabinet similar to that shown in FIG. 2. Into thatmetal frame may be mounted a slidable drawer. The slidable drawer inthis embodiment is formed of electrically inert material, that is, it isnot electrically conductive, except for the front. When the drawer isslid into the cabinet to a closed configuration, the electricallyconductive front panel of the drawer comes into electrical contact withanother part or parts of the metallic frame 167 thereby forming thefront wall 161 of the Faraday cage 167.

The amount of penetration or retention into the cavity by the centralconductor 180 of each probe is selected so as to achieve optimumcoupling. The length of the bent portion 94 of the probe is selected toresult in better impedance matching. The position of the probe inrelation to the walls of the cavity is selected to create a standingwave in the cavity. In this embodiment, the probe antennae 162 and 164have been located at a particular distance D1 and D3 from respectivefront 161 and back 170 walls. These probe antennae, in accordance withone aspect of the invention, are only activated sequentially after theother probe has become inactivated. It has been found that thisconfiguration results in a standing wave where the injected energy wavesare in phase so that constructive interference results.

FIG. 14 is a front perspective view of the probe configuration of FIG.13 again showing the two probe antennae 162 and 164 located in aFaraday-type enclosure 166 for establishing a robust EM field in anarticle storage drawer to be inserted. It should be noted again that theFaraday cavity 166 is constructed as a metallic frame 167. In thisfigure, the cavity is incomplete in that the front surface of the “cage”is missing. In one embodiment, this front surface is provided by anelectrically conductive front panel of a slidable drawer. When thedrawer is slid into the cabinet, the front panel will make electricalcontact with the other portions of the metallic frame 167 therebycompleting the Faraday cage 166, although other portions of the drawerare plastic or are otherwise non-electrically conductive. In theembodiment discussed and shown herein, the two probe antennae 162 and164 are both located along a centerline between the side walls 166 and168 of the frame 166. The enclosure in one embodiment was 19.2 incheswide with the probe antennae spaced 9.6 inches from each side wall. Thiscentered location between the two side walls was for convenience in thecase of one embodiment. The probes may be placed elsewhere in anotherembodiment. In this embodiment, the spacing of the probes 162 and 164from each other is of little significance since they are sequentiallyactivated. Although not shown, two receiving antennae will also beplaced into the Faraday cage 166 to receive response signals from theactivated RFID tags residing within the cavity 166.

It will also be noted from reference to the figures that the probes eachhave a bent portion used for capacitive coupling with the ceiling 160 ofthe cavity, as is shown in FIG. 13. The front probe 162 is bent forwardwhile the back probe 164 is bent rearward A purpose for thisconfiguration was to obtain more spatial diversity and obtain bettercoverage by the EM field established in the drawer. Other arrangementsmay be possible to achieve a robust field within the cavity 166.Additionally two probes were used in the particular enclosure 166 sothat better EM field coverage of the enclosure 166 would result.

FIG. 15 is a cutaway perspective side view of the dual probe antennae162 and 164 of FIGS. 13 and 14, also with the drawer removed forclarity. The front probe 162 is spaced from the left side wall by ½ λ ofthe operating frequency F_(f) as shown. It will be noted that the probeseach have a bent portion used for capacitive coupling with the ceiling160 of the enclosure 166 as shown in FIG. 13. The front probe 162 isbent forward for coupling with the more forward portion of the enclosurewhile the back probe 164 is bent rearward for coupling with the morerearward portion of the enclosure 166 to obtain more spatial diversityand obtain better coverage by the EM field in the drawer. Otherarrangements may be possible to achieve a robust field and furtherspatial diversity and coverage within the enclosure.

FIG. 16 is a frontal upward-looking perspective view of the frame 167forming a Faraday cage 166 showing a portion of a drawer 180 that hasbeen slidably mounted within the frame 167. The front metallic panel ofthe drawer has been removed so that its sliding operation can be moreclearly seen. It will also be noted that the dual ceiling mount probeantennae 162 and 164 have been covered and protected by anelectromagnetically inert protective cover 182. The drawer is formed ofa non-metallic material, such as a plastic or other electromagneticinert material having a low RF constant. The back 184 of the drawer hasalso been cut away so that a cooling system 189 comprising coils 186 anda fan 188 located in the back of the frame 167 can be seen. In thiscase, the drawer 180 is slidably mounted to the Faraday cage frame withmetallic sliding hardware 190. The sliding hardware of the drawer is sonear the side of the frame 167 of the enclosure 166 and may be inelectrical contact with the metallic slide hardware of the side walls168 of the enclosure that these metallic rails will have only a smalleffect on the EM field established within the enclosure.

FIG. 17 is an upward looking, frontal perspective view at the oppositeangle from that of FIG. 16; however, the drawer has been removed. Theframe 167 in this embodiment includes a mounting rail 192 for receivingthe slide of the drawer 180. In this embodiment, the mounting rail isformed of a metallic material; however, it is firmly attached to a side168 of the Faraday cage and thus is in electrical continuity with thecage. The figure also shows a spring mechanism 194 used to assist insliding the drawer outward so that access to the articles stored in thedrawer may be gained. The spring is configured to automatically push thedrawer outward when the drawer's latch is released.

FIG. 18 is a schematic view showing measurements of the placement of twoTE₀₁ mode capacitive coupling probes 162 and 164 in the ceiling 160 ofthe frame 167 shown in FIGS. 13-15. In this embodiment, the frequency ofoperation with the RFID tags is 915 MHz, which therefore has awavelength of 0.32764 meters or 1.07494 feet. One-half wavelength istherefore 0.16382 meters or 6.4495 inches. The length of the capacitivecoupling bent portion 200 of each of the probes is 5.08 cm or 2.00 in.The length of the axial extension 202 of the probes into the enclosureis 3.81 cm or 1.50 in., as measured from the insulator 204 into theenclosure 166. The probe configuration and placement in the embodimentwas based on an operation frequency of 915 MHz. In one embodiment, theenclosure 166 had a depth of 16.1 inches (40.89 cm), a width of 19.2inches (48.77 cm) and a height of 3 inches (7.62 cm). It was found thatthe optimum probe placements for this size and shape (rectangular)enclosure and for the 915 MHz operating frequency were: the front probewas spaced from the front wall by 5.0 inches (12.7 cm) and the rearprobe was spaced from the back wall by 5.0 inches (12.7 cm). As discussabove, the probes in this embodiment would only be activatedsequentially.

FIG. 19 is a schematic view of the size and placement within theenclosure 166 of FIG. 16 of two microstrip or “patch” antennae 210 and212 and their microstrip conductors 214 and 216 disposed between therespective antennae and the back of the enclosure at which they will beconnected to SMA connectors (not shown) in one embodiment. Feed lines 58(FIG. 3) may be connected to those SMA connectors and routed to thecomputer 44 for use in communicating the RFID signals for furtherprocessing. The measurements of the spacing of some of the microstripcomponents are provided in inches. The spacing of 9.7 in. is equivalentto 24.64 cm. The width of the microstrip line of 0.67 in. is equivalentto 17.0 mm. The spacing of 1.4 in. is equivalent to 3.56 cm. Otherconfigurations and types of receiving antennae may be used, as well asdifferent numbers of such antennae. In the present embodiment, thereceiving antennae are mounted on insulation at the bottom insidesurface of the metallic enclosure frame 167 so that the receiving patchantennae are not in contact with the metal surfaces of the Faraday cage.

Referring now to FIG. 20, the field intensity or field strength in theenclosure discussed above is shown with the ordinate axis shown involts/meter and the abscissa axis shown in meters. It will be seen fromthe diagram that the maximum field intensity occurs at about 5.0 inches(0.127 m) which results from the probe positioned at 5.0 inches (12.7cm) from the front wall and at a 915 MHz operating frequency. Referringnow to FIG. 21, the scale has been reduced although the large rise infield intensity can be seen at 5.0 inches. It can also be more clearlyseen that the field intensity falls off at the right wall but remainsstrong very close to the left wall. Therefore in an embodiment, a secondprobe was used that was placed 5.0 inches (12.7 cm) from the right wallthereby resulting in a mirror image field intensity to that shown inFIG. 21. The two probes 162 and 164 are activated sequentially and arenot both activated simultaneously. It will be noted that better EM fieldcoverage of the enclosure 166 is obtained with the two probes and thatRFID tags on articles positioned close to the front wall 161 will beactivated by the front probe 162 and that RFID tags on articlespositioned close to the rear wall 170 will be activated by the rearprobe 164 (see FIG. 13).

Although not intending to be bound by theory, in deriving the probelocation for TE modes in a square or rectangular non-resonant cavity,the following equation can be useful:

$N = {2 \times \frac{L_{2} - L_{1}}{\lambda_{g}}}$

where:

-   -   N=positive non-zero integer, for example 1, 2, 3, etc.    -   L₁=distance between probe and back wall    -   L₂=distance between probe and front wall    -   λ_(g)=wavelength in the cavity

L₁ cannot be zero for TE modes, which implies that the probe for TE modeexcitation cannot be at the front or back wall. For TM modes, theequation is the same, but N can equal zero as well as other positiveintegers. The probe position cannot be λ_(g)/2 from the front or backwall. An L₁ and an L₂ are chosen such that N can be a positive integerthat satisfies the equation. For example, for the enclosure 166discussed above:

L₁=4.785 inches

L₂=11.225 inches

λ_(g)=12.83 inches

Therefore,

$N = {{2 \times \frac{11.215 - 4.785}{12.83}} = 1.0}$

The actual enclosure had the probe located at a slightly differentlocation (5.0 inches) than that indicated by the equation (4.785 inches)which was possibly due to the insertion of a plastic drawer in thecavity, which introduces a change in the phase from the reflectedsignals. The equation above is set up such that the reflected phase fromboth front and back walls is equal, i.e., they are “in phase” at theprobe location.

The wavelength in the enclosure, λ_(g), can be calculated usingwaveguide equations. Equations for a rectangular cavity are shown below.The cutoff frequency is required for this calculation. The equationswill change for a cylindrical cavity or for other shapes.

The cutoff frequency is at the point where g vanishes. Therefore, thecutoff frequency in Hertz is:

$\left( f_{c} \right)_{mn} = {\frac{1}{2\;\pi\sqrt{\mu\; ɛ}}\sqrt{\left( \frac{m\;\pi}{a} \right)^{2} + \left( \frac{n\;\pi}{b} \right)^{2}}({Hz})}$

The cutoff wavelength in meters is:

$\left( \lambda_{c} \right)_{mn} = {\frac{2}{\sqrt{\left( \frac{m}{a} \right)^{2} + \left( \frac{n}{b} \right)^{2}}}(m)}$

where:

-   -   a=inside width    -   b=inside height    -   m=number of ½-wavelength variations of fields in the “a”        direction    -   n=number of ½-wavelength variations of fields in the “b”        direction    -   ∈=permittivity    -   μ=permeability

The mode with the lowest cutoff frequency is called the dominant mode.Since TE₁₀ mode is the minimum possible mode that gives nonzero fieldexpressions for rectangular waveguides, it is the dominant mode of arectangular waveguide with a>b and so the dominant frequency is:

$\left( f_{c} \right)_{10} = {\frac{1}{2\; a\sqrt{\mu\; ɛ}}({Hz})}$

The wave impedance is defined as the ratio of the transverse electricand magnetic fields. Therefore, impedance is:

$Z_{TE} = {\frac{E_{x}}{H_{y}} = {\frac{j\; w\;\mu}{\gamma} = {\left. \frac{j\; w\;\mu}{j\;\beta}\Rightarrow Z_{TE} \right. = \frac{k\;\eta}{\beta}}}}$

The guide wavelength is defined as the distance between two equal phaseplanes along the waveguide and it is equal to:

$\lambda_{g} = {{\frac{2\;\pi}{\beta} > \frac{2\;\pi}{k}} = \lambda}$where${k_{c} = \sqrt{\left( \frac{m\;\pi}{a} \right)^{2} + \left( \frac{n\;\pi}{b} \right)^{2}}};{and}$$\beta = \sqrt{k^{2} - k_{c}^{2}}$

FIGS. 22A and 22B together provide a block electrical and signal diagramfor a multiple-drawer medical cabinet, such as that shown in FIG. 2. Inthis case, the cabinet has eight drawers 220, shown in both FIGS. 22Aand 22B. Each drawer includes two top antennae, two bottom antennae anda lock with a lock sensor 222 for securing the drawer. Signals to andfrom the antennae of each drawer are fed through an RF multiplexerswitch 224. Each RF multiplexer switch 224 in this embodiment handlesthe routing of RF signals for two drawers. RFID activation field andRFID received signals are fed through the respective RF multiplexerswitch 224 to a main RFID scanner 230 (see FIG. 22B). The scanner 230output is directed to a microprocessor 232 (see FIG. 22B) for use incommunicating relevant information to remote locations, in this case bywired connection 234 and wireless connection 236 (see FIG. 22B). Varioussupport systems are also shown in FIGS. 22A and 22B, such as powerconnections, power distribution, back up battery (see FIG. 22B),interconnection PCBA, USB support (see FIG. 22A), cooling (see FIG.22B), and others.

In accordance with one embodiment, drawers are sequentially monitored.Within each drawer, the antennae are sequentially activated by theassociated multiplexer 224. Other embodiments for the signal andelectrical control systems are possible.

Although RFID tags are used herein as an embodiment, other data carriersthat communicate through electromagnetic energy may also be usable.

Refrigerated Drawer

Referring now to FIG. 25, a generally non-metallic slidable drawer 330is configured to be mounted within a medication cabinet 332. It includesvarious dividers or partitions 334 in the drawer that form “pockets” 336within which are placed medical articles for storage and administration.The cabinet within which the drawer is slidably mounted includes ametallic frame 338 surrounding the drawer to operate as a Faraday cage.Also now referring to FIG. 26, the front portion 340 of the drawer 330may be formed of metal 342 or include a metallic portion that contactsthe remainder of the metallic frame 338 of the cabinet 332 when thedrawer is in the closed configuration to complete the Faraday cagearound the drawer. Within that frame is included an RF system fordetecting the existence of RFID tagged articles placed in the drawer asdiscussed above in further detail.

Referring now to FIG. 16, in accordance with another aspect of theinvention, a thermoelectric cooling (“TEC”) device 189 is disposed atthe back of the metallic frame 170. See also FIG. 30 showing theposition of a TEC device 189 that has been mounted to the drawer andmoves with it to the open and closed positions. In one embodiment theTEC device is located at a corner of the back of the drawer as opposedto being centrally located. An RFID reader 182 for detecting RFID taggedarticles in the drawer 180 is included in the frame about the drawerwith the probes 162, 164 being centrally placed above the drawer in thisembodiment. Therefore, there is less room available for a TEC device 189in the center of the drawer. Additionally, it was noticed by theinventors that the TEC device must actually extend somewhat into thedrawer due to a need to keep the medication cabinets and drawers at asmaller size. When the TEC device is located at a corner of the back ofthe drawer, it was found that it only interferes with two pockets 336 ofthe drawer, as seen in FIG. 25. However, if it is placed in the centerof the drawer, it would interfere with three pockets, thereby resultingin less storage room for storing medical articles in a drawer.

In an embodiment of the invention, a Peltier TEC device 189 was used.Such units are available from TE Technology, Inc., having an address of1590 Keane, Traverse City, Mich., part number AC-073 (www.tetech.com).In this embodiment, a Peltier-type unit was used due its small size,semi-conductor nature, availability, and sufficient cooling capacity.The use of such units provides significant advantages, one of which isthe lack of vibration since no compressor is needed. However, theinvention is not limited to only thermo-cooling type units, but othersthat exist now or may become available in the future can be used.

One of the advantages of the invention is that a cabinet of the presentembodiment has both cooled and uncooled drawers. In the prior art,cabinets were either completely refrigerated or completelynon-refrigerated as was discussed in detail above in the Backgroundsection. This is an undesirable approach since two cabinets arenecessary for the two different types of medications, one of whichrequires constant cooling, and the other of which needs to be at roomtemperature for use. Thus, a cabinet that is able to provide bothrefrigerated and non-refrigerated drawers is needed in the art and isprovided here.

Referring again to FIG. 25 and also to FIG. 27, a TEC device enclosure350 is shown at the rear corner of the drawer 330. In FIG. 25, thisenclosure 350 is covered but FIG. 27 shows it more clearly. Thisenclosure is a part of the “real estate” of the drawer and is used toreceive the TEC device when the drawer is in the closed position. Itwill be noted that holes 352 are formed in the enclosure 350 in thefront and side partitions 334 which operate to diffuse the coolingeffect of the TEC device. FIG. 16 also shows that the TEC device 189 ofthis embodiment includes a fan 188 that, when combined with thediffuser, lowers or eliminates any temperature gradients that may tendto exist in the drawer 330 (FIG. 25). The size and locations of thepartitions 334 also assist in lowering any temperature gradients as wellas the holes 360 formed in the partitions.

In one embodiment, the TEC device 189 is anchored to the frame of thecabinet 300 and the drawer 330 engages it when closed and is moved awayfrom it when open. This configuration is shown in FIG. 16. This permitsambient air to have a greater effect on the contents of the drawer whenthe drawer is in the open position. In another embodiment as shown inFIG. 30, the TEC device is anchored to the drawer 330 and moves with thedrawer when the drawer is opened. This will permit the cooler air fromthe TEC device to be continually present thus lessening the effect ofthe ambient air on the drawer contents when the drawer is open.

Returning again to the drawer 330, an RF drawer as contemplated by theinvention uses both electrical insulation and thermal insulation. Theelectrical insulation is provided by locating electrically conductivematerials about the drawer on all sides to form the required Faradaycage, some of which is shown in FIG. 25 as the frame 338 and as shown inFIG. 28, which shows a portion of the cabinet with a drawer removed. Thethermal insulation 344 is provided by the use of standard thermalinsulation available widely. In some cases where large surface areas areavailable, slabs of the thermal insulation are cut at the appropriatesizes and installed in the framework around the location of the drawer330 as shown in FIG. 28. As shown in FIG. 29, the front 340 of thedrawer 330 may also have insulation 344 located within it. In areas suchas the back of the drawer where there are electrical conductors andother equipment used in conjunction with the drawer, spray-typeinsulation (not shown) may be used after the manufacture of the draweris completed to place the required thermal insulation around the drawer.Use of a high quality thermal insulation, such as Semi-Rigid PVC Foam,not only keeps the cool air within the drawer when the drawer is in theclosed position, but also protects adjacent drawers from coolingproduced by the TEC device 189 for that particular drawer. It has beenfound that with the proper amount of insulation, adjacent drawers are atroom temperature while the refrigerated drawer may be held at a range of3-10° C.

In one embodiment, the TE Technology Peltier thermoelectric coolermodule 189 listed above was used and had a capacity of 73 watts at a 0°temperature difference. The medication cabinet 300 in which it wasinstalled for refrigerating a single drawer 330, held a total of 5drawers. It was found that by using a Peltier unit of this capacity withthe surrounding insulation approach discussed above and shown in thedrawings, the target drawer was kept at the temperature desired andadjacent drawers were able to remain at room temperature. Furthermore,the power requirements and size of the TEC device are substantiallyreduced compared to the traditional compressor-based systems.

In another feature, the TEC devices 189 for the drawers 330 of thecabinet 300 may be selectively turned off so that the cooling system isnot running and the drawer can be at ambient temperature. This allowsthe healthcare facility to lower costs since the TEC device 189 will notneedlessly be consuming electricity.

In a further feature, the drawers 330 include at least one temperaturesensor 370. The temperature data from these sensors are communicated tothe control unit 306 for monitoring. Should the temperature of arefrigerated drawer rise above a selected threshold, an alarm may beprovided at the display 304. Additionally the control unit 306, server310, and data base 320 may cooperate to conduct temperature data loggingfor historical charting and analysis. In the embodiment of FIG. 30, anambient temperature sensor 372 is provided. This sensor is located at aposition away from the heat exhaust of the TEC device or devices so thatits reading is not influenced by those exhausts. Having a single ambienttemperature sensor obviates the need for a sensor in each of thenon-refrigerated drawers. Since those drawers have no temperaturecontrol devices affecting them, it is presumed that they are at theambient temperature.

This invention utilizes a data base 320 that a healthcare institutioncan maintain to list medications and other medical supplies that requirerefrigerated conditions. In addition, there is an RFID system thatdetermines the need for and controls the environment of refrigeratedmedications within an RFID-enabled dispensing cabinet 300 or mobile cart318. The system will automatically determine via the database whatconditions a medication that has been loaded into it will require andmake the necessary inputs/outputs to insure the medication'senvironmental requirements are maintained as well as recorded on apre-determined time interval basis for history record purposes.

When a medication 378 is placed into the RFID dispensing cabinet 300 ormobile cart 316, the system recognizes the need for refrigeration, ifrequired. This recognition may occur in different ways. In one way, theRFID tag associated with the medication may be coded to indicate thattemperature control is required and at what temperature. In another way,the control unit 306 receives the identification of the medication inthe drawer 330 from the RFID detection system, accesses the remoteserver 310 and its data base 320, and receives the data about thisidentified medication indicating that the medication needs temperaturecontrol and the temperature required.

A “smart” system via the host computer 306 determines the need forrefrigeration and effects the necessary outputs to provide the correctenvironmental conditions for such. Turning in more detail to FIG. 30 andto FIG. 31, a system and method are presented for this “smart” system.In FIG. 30, a cabinet 300 is shown with a drawer 330 open. Pockets ofthe drawer are shown and some of those pockets contain medications 378,each of which has an RFID tag. When the drawer is pushed back into thecabinet, the RFID system automatically detects the tag of the medicationand reads it 400. In one embodiment, the control unit 306 receives thedata from that RFID tag, automatically contacts the remote server 310and looks up 402 the medication in the data base 320. The control unitthen determines if the medication requires temperature control 404. Ifit does require temperature control, the control unit automaticallymeasures the temperature of the ambient air 406 through reference to theambient air sensor 372 to determine if a refrigerated drawer is needed408. If the ambient air temperature meets the requirement for thetemperature controlled medication 378, the control unit then continuesto monitor the ambient temperature to be sure that no changes areoccurring.

In another embodiment, the RFID tag placed on each medication 378includes a temperature sensor, and part of the data transmitted by theRFID tag for that medication includes the temperature of the medication.

If the ambient temperature is not consistent with the temperaturerequirement of the medication, the control unit determines if the drawerin which the medication has been placed can be temperature controlled410. If it cannot, an alert is automatically provided 412 that themedication must be moved to a refrigerated drawer. Once the medicationis moved to a refrigerated drawer, the RFID system once againautomatically determines its presence in that drawer and the controlunit 306 then sets the temperature 414 for the TEC device to maintainfor the medication.

Another feature in accordance with aspects of the invention is thattemperature monitoring and logging occur. The control unit 306determines if a temperature controlled (TC) medication is located in adrawer 420. If so, the temperatures sensors 370 of that drawer aremonitored 422 by the control unit 306 and are periodically logged 424 asrequired by the policies of the healthcare institution or otherauthorities. When needed, the logs may be printed or forwarded elsewherein digital form.

Turning now to FIG. 32, a block diagram of a system 440 in accordancewith aspects of the invention is shown. An RFID detector system 442located in a drawer of a cabinet detects the existence of a medical itemhaving and RFID tag. The detector system 442 provides the data read fromthe RFID tag to the processor 444. The processor then accesses theserver 446 and the associated data base 448 to determine thecharacteristics of the detected medical item and to determine if it hasany temperature control requirements. Other data about the medical itemmay be of importance in tracking the item, and for other purposes.

If the medical item requires temperature control, the processor accessesthe ambient temperature sensor 450 to determine if the ambienttemperature satisfies the medical item's requirements. If the medicalitem needs a temperature below the ambient temperature, the processorwill determine if the medical item is currently in a temperaturecontrolled drawer of the medical cabinet. If it is not, the processorwill display an ALERT message on the display 452 to have a user move themedical item to a temperature controlled drawer. Once this has beendone, the RFID detector system 442 will automatically detect thepresence of the medical item in a temperature controlled drawer and willinform the processor 444. The processor will then set the TEC device 454of that drawer to the correct temperature to be maintained. The TECdevice will automatically maintain the temperature of that drawer to thetemperature required for the medical item. The system 440 of FIG. 32 mayhave another one or more temperature controlled drawers with a sensor460 and TEC device 462.

The same is true of removal of the temperature controlled medicationfrom a drawer. The processor monitors all medications delivered to thedrawer and removed from the drawer and automatically controls therefrigeration device accordingly. If there are no more medications leftin the drawer that have temperature control requirements, the processorwill automatically deactivate the refrigeration unit of that drawer andallow the drawer to return to ambient temperature, thus conservingenergy.

In another feature, the processor monitors the temperature sensor 456 ofthat drawer and creates a log 470 concerning that medical item and thesensed temperature at which it was kept, at intervals as required, forexample twice per day. The log may be kept in a processor memory,forwarded to a server, or otherwise stored or printed. Various detailsmay be included in the log, such as cabinet identification, draweridentification, temperature sensor type, calibration date, arrival dateand time, removal date and time, and other data, as required.

Thus an RFID enabled drawer refrigeration system provides numerousadvantages. Selective cooling of certain drawers may occur while otherdrawers are at room temperature. Because of this feature, only onecabinet is needed for both refrigerated medical articles and roomtemperature medical articles. There is a modular design in that thedrawers are configurable and selectable between refrigerated and ambienttemperatures.

Unless the context requires otherwise, throughout the specification andclaims that follow, the word “comprise” and variations thereof, such as,“comprises” and “comprising” are to be construed in an open, inclusivesense, which is as “including, but not limited to.”

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments and elements, but, to the contrary, is intended tocover various modifications, combinations of features, equivalentarrangements, and equivalent elements included within the spirit andscope of the appended claims.

We claim:
 1. A cabinet for storing items, the cabinet having a depth andcomprising: a plurality of drawer cavities, each cavity configured toreceive a drawer, each cavity having a front opening through which thedrawer is moved to a closed position within the cavity and through whicheach drawer is moved to an open position in which the drawer is at leastpartially outside of the cavity; an electrically conductive cage formedabout a first cavity, the cage having a cage front located at the frontopening of the cavity; a plurality of drawers, each of which is receivedby a respective cavity and which is movable to an open position and to aclosed position, with a first drawer being received by the first cavityhaving the electrically conductive cage; a temperature control deviceconfigured to provide temperature control for a single drawer, thetemperature control device mounted to at least one of: the first drawerso as to move with the drawer; and at a fixed position in relation tothe first cavity; a second cavity adjacent the first cavity, the secondcavity having no temperature control device and being at ambienttemperature; thermal insulation disposed between the first and secondcavities, the thermal insulation located and configured to inhibitcooling provided by the temperature control device of the first cavityfrom reaching a drawer that is located in the second cavity; and an RFIDreader disposed within the first cavity and configured to read RFID tagdata from an RFID tag located within the first drawer.
 2. The cabinet ofclaim 1 wherein the temperature control device is mounted in a fixedposition in relation to the first cavity such that the first drawermoves toward the temperature control device when the drawer is moved tothe closed position and moves away from the temperature control devicewhen the drawer is moved to the open position.
 3. The cabinet of claim 2wherein the first drawer includes a temperature control device enclosureformed at a rear portion of the first drawer, the temperature controldevice enclosure being configured to receive the temperature controldevice into the temperature control device enclosure when the drawer isin the closed position, whereby the depth of the cabinet is reduced. 4.The cabinet of claim 3 wherein the temperature control device enclosurecomprises a diffuser located and configured to assist in diffusing andcirculating cooling from the temperature control device more equallythroughout the first drawer.
 5. The cabinet of claim 4 wherein the firstdrawer having the temperature control device enclosure further includespartitions disposed in the first drawer to separate items from oneanother when stored in the first drawer, the partitions having openingsconfigured such that cooling from the temperature control device isallowed to circulate throughout the first drawer through the openings ofthe partitions.
 6. The cabinet of claim 1 wherein the first drawer isslidable into and out of the first cavity, the drawer having a frontpanel that is electrically conductive and that contacts the front of theelectrically conductive cage when the drawer is slid to the closedposition thereby completely closing the electrically conductive cageabout the first drawer.
 7. The cabinet of claim 1 further comprising: atemperature sensor located so as to measure temperature in the firstdrawer and to provide temperature data representative of the sensedtemperature, a control unit programmed to receive the sensed temperaturedata, compare it to a selected temperature, and control the temperaturecontrol device to maintain temperature in the first drawer at a selectedlevel.
 8. The cabinet of claim 7 wherein the control unit is furtherprogrammed to record the received temperature data from the first drawersensor in a memory.
 9. The cabinet of claim 1 further comprising: atemperature sensor located to measure temperature in the first drawerand to provide temperature data representative of the sensedtemperature; a control unit programmed to receive RFID tag data from theRFID reader regarding an item located in the first drawer and receivesensed temperature data from the temperature sensor regarding thetemperature of the first drawer; wherein the control unit is furtherprogrammed to: determine from the received RFID tag data whether an itemresiding in the first drawer requires a particular temperature; if thecontrol unit determines that an item residing in the first drawer doesrequire a particular temperature, then compare that temperature to thesensed temperature data; and control the temperature control device tomaintain the particular temperature in the first drawer.
 10. The cabinetof claim 9 wherein the control unit is further programmed to receiveRFID tag data having temperature requirements included in said RFID tagdata and to control the temperature control device in accordancetherewith.
 11. The cabinet of claim 9 wherein the control unit isfurther programmed to: receive from the RFID reader RFID tag data thatcomprises an identification of the RFID tag that was read by the reader;access a data base that correlates RFID tag identification data to aparticular item and from a correlation of the received RFIDidentification data, identify an item, and from a data base, determinewhether the identified item has a temperature requirement and if so,control the temperature control device in accordance therewith.
 12. Thecabinet of claim 9 wherein the control unit is further programmed to:receive RFID tag data that comprises an identification of the tag;determine from the received RFID tag data whether any item residing inthe first drawer requires a particular temperature; if the control unitdetermines that no item residing in the first drawer requires aparticular temperature, then control the temperature control device tostop operating.
 13. The cabinet of claim 9 further comprising an ambienttemperature sensor located to sense ambient temperature around thecabinet and provide ambient temperature data representative thereof;wherein if the control unit determines from RFID tag data that an itemresiding in the first drawer requires a particular temperature, thecontrol unit is further programmed to compare the sensed ambienttemperature data to that required temperature and if the ambienttemperature satisfies the required temperature, allow the temperaturecontrol device to remain off.
 14. The cabinet of claim 9 wherein thecontrol unit is further programmed to determine if a plurality of itemsresiding in the first drawer require particular temperatures, and if so,then compare those required temperatures to one another, and if thecompared required temperatures differ, provide an alert thatnon-compatible temperature-control items reside in the same drawer. 15.The cabinet of claim 1 further comprising: a second RFID reader disposedwithin the second cavity and configured to read RFID tag data from anRFID tag located within the second drawer; a control unit programmed toreceive RFID tag data from the second RFID reader regarding an itemlocated in a non-temperature controlled second drawer; the control unitfurther programmed to determine from the received RFID tag data whetheran item residing in the second drawer requires a particular temperature,and if the control unit determines that an item residing in the seconddrawer does require a particular temperature, then provide an alert thata temperature-controlled item has been placed in the second drawer. 16.The cabinet of claim 15 further comprising an ambient temperature sensorlocated to sense ambient temperature around the cabinet and provideambient temperature data representative thereof; wherein the controlunit is further programmed to determine from RFID tag data that an itemresiding in the second drawer requires a particular temperature,comparing the sensed ambient temperature data to that requiredtemperature, and if the ambient temperature satisfies the requiredtemperature of the item in the second drawer, provide an alert that atemperature-controlled item has been placed in the second drawer butthat ambient temperature presently satisfies the temperature requirementof said item.
 17. A cabinet for storing items, comprising: a pluralityof drawer cavities, each cavity configured to receive a drawer, eachcavity having a front opening through which the drawer is moved to aclosed position within the cavity and through which each drawer is movedto an open position in which the drawer is at least partially outside ofthe cavity; a plurality of drawers, each of which is received by arespective cavity and which is movable to an open position and to aclosed position; a temperature control device configured to providecooling for a single drawer, the temperature control device mounted at afixed position in relation to the first cavity; wherein a second cavitylocated adjacent the first cavity has no temperature control device andis at ambient temperature; thermal insulation disposed between the firstand second cavities, the thermal insulation located and configured toinhibit cooling provided by the temperature control device of the firstcavity from reaching a drawer that is located in the second cavity; afirst RFID reader disposed within the first cavity and configured toread RFID tag data from an RFID tag located within the first drawer; asecond RFID reader disposed within the second cavity and configured toread RFID tag data from an RFID tag located within the second drawer; atemperature sensor located to measure the temperature in the firstdrawer and to provide temperature data representative of the sensedfirst drawer temperature; a control unit programmed to receive RFID tagdata from the first RFID reader regarding an item located in the firstdrawer and receive sensed temperature data from the first drawertemperature sensor regarding the temperature of the first drawer;wherein the control unit is further programmed to: determine from thereceived RFID tag data whether an item residing in the first drawerrequires a particular temperature; if the control unit determines thatan item residing in the first drawer does require a particulartemperature, then compare that temperature to the sensed temperaturedata; control the temperature control device to maintain the particulartemperature in the first drawer; and record the received temperaturedata from the first drawer sensor in a memory; and wherein the controlunit is further programmed to receive RFID tag data from the second RFIDreader regarding an item located in a non-temperature controlled seconddrawer, determine from the received RFID tag data whether an itemresiding in the second drawer requires a particular temperature, and ifthe control unit determines that an item residing in the second drawerdoes require a particular temperature, then provide an alert that atemperature-controlled item has been placed in the second drawer. 18.The cabinet for storing items of claim 17 wherein the control unit isfurther programmed to receive RFID tag data that comprises anidentification of the tag and access a data base that correlates RFIDtag identification data to a particular item and from a data base,determine whether the identified item has a temperature requirement andif so, control the temperature control device in accordance therewith.19. A method of storing items, comprising: storing items in a pluralityof drawers in a cabinet, each of which is configured to move into andout of a respective cavity to a closed position within the cavity and toan open position in which the drawer is at least partially outside ofthe cavity; mounting a temperature control device to provide temperaturecontrol only to a first drawer located in a first cavity; insulating thefirst cavity from a second cavity located adjacent the first cavity toinhibit temperature control provided to the first drawer in the firstcavity from reaching the second cavity and second drawer and tending tokeep the second cavity and drawer at ambient temperature; sensingtemperature in the first drawer and logging temperature readings overtime; reading RFID tag data from an RFID tag disposed on an item locatedin the first drawer to determine if a temperature requirement exists forthe item to which the tag is attached; if a temperature requirement isdetermined to exist for the item in the first drawer, controlling thetemperature in the first drawer with the temperature control device tosatisfy the temperature requirement; reading RFID tag data from an RFIDtag disposed on an item located in the second drawer to determine if atemperature requirement exits for the item to which the tag is attached;if it is determined that the item in the second drawer has a temperaturerequirement, providing an alert that a temperature-controlled item hasbeen placed in the second drawer.
 20. The method of storing items ofclaim 19 wherein: the step of reading RFID tag data from an RFID tagdisposed on an item located in the first drawer comprises reading with afirst RFID reader; and the step of reading RFID tag data from an RFIDtag disposed on an item located in the second drawer comprises readingwith a second RFID reader that is separate from the first RFID reader.